煤系岩样单轴压缩表面电位实验研究

Experimental Study on Surface Potential of Coal Measures Rock Samples Under Uniaxial Compression

实验研究了煤系岩样在单轴压缩条件下表面电位特征,并分析了表面电位的变化规律与产生原因。研究表明:煤系岩样在单轴压缩的破坏过程中有表面电位产生;载荷发生突变时,表面电位也发生突变;总体上,表面电位与载荷变化趋势一致,呈显著相关甚至是高度相关;表面电位的产生主要来源于破坏过程中试样内部的应力集中发射电子、裂纹扩展导致电荷分离等过程所产生的自由电荷在试样表面积聚的结果;试样含有石英等成分所产生的压电效应也对电位的产生有重要作用。可以通过检测表面电位的变化规律来反映煤系岩样的受载破坏情况,为矿山岩体稳定性的监测提供新的思路。

The experimental research was made on the surface potential characteristics of coal measures rock samples under uniaxial compression, and the laws and reasons of surface potential were discussed. The results showed that the surface potential produced in the sample failure process under uniaxial compression. When the load changed suddenly, the surface potential would change as well. On the whole, the change trends of surface potential and load were same, which were significant correlation, even highly correlation. The surface potential mainly came from the free charge accumulating on the surface of sample in the internal failure process. The free charge produced during electronic emission from stress concentration and charge separation during crack growth. The piezoelectric effect caused by the composition of a certain amount of quartzes also played an important role for surface potential. The change laws of surface potential could reflect the destruction of coal measures rock samples under the load, which provided a new way for the rock stability monitoring.